Control pedals for vehicle are well known. Some such pedals actuate mechanical linkages to hydraulic master cylinders and tension and release control cable, such as accelerator or parking brake cables. Conventional parking brake pedal mechanisms typically have a release handle to release the pedal to remove tension from the control cable or, more recently, a push to release pedal mechanism is offered wherein the parking brake is actuated by first pressing the brake pedal and is subsequently released by again pressing the brake pedal.
Examples of push to release pedal systems include U.S. Pat. No. 4,872,368 to Porter; U.S. Pat. No. 5,217,094 to Walter et al.; U.S. Pat. No. 5,588,335 to Strait; and U.S. Pat. No. 5,775,174 to Kanbe et al.
The above-described pedal activated parking brake systems conventionally employ a ratchet and pawl arrangement to lock the mechanism in the engaged position to maintain the tension on the parking brake cable. While such systems work well, they do suffer from a disadvantage in that, when the brake is set, the pawl is dragged across on the teeth of the ratchet resulting in a relatively loud noise which is apparent to the vehicle operator.
To eliminate this noise, a “quiet apply” brake systems have been created. Published U.S. patent application 2003/0084743 teaches one such system which is a simple and effective quiet apply mechanism and the contents of that applications are incorporated herein by reference. This quiet apply mechanism employs a clutch spring which maintains a cam biased against a stop and which maintains the tension in the parking brake cable. When a release actuator is operated by a driver, tension is removed from the clutch spring, allowing the cam to release from the stop and releasing the tension in the brake cable.
To date, no one has offered a quiet apply mechanism in a push to release parking brake system.